Pivotally mounted guard for tractor chain and supporting rollers



Feb. 5, 1957 F. L. LAWSON 2,780,500

FIVOTALLY MOUNTED GUARD FOR TRACTOR CHAIN AND SUPPORTING ROLLERS Filed Sept. 12, 1955 FIG. 3

INVENTOR. FRANK L. LAWSON BY Z a/4'4,

ATTORNEYS PIVOTALLY MOUNTED GUARD FOR TRACTOR CHAIN AND SUPPORTING ROLLERS Frank L. Lawson, San Diego, Calif., assignor to Caudell fa Johnson, San Diego, Calif.,a corporation of Caliornia Application september 12,1955, Serial No. 533,716 4 Claims. c aos-9 The present invention relates to crawler type tractors having front and rear sprocket wheels; an endless chain, carrying shoes, is trained about the wheels; such type of tractor includes rollers which are interposed between the top side of the lower run of the chain and the tractor frame for supporting the frame.

Inasmuch as such tractors are commonly used for moving gravel and stones, at times stones become lodged between the rollers, and quite often such clogging is such that mechanical parts of the machinery are broken or bent to such an extent as to render the mechanism inoperative.

I am aware that guards have been provided lying alongside the lower run of the chain, yet quite often stones are picked up between the guard and chain, become lodged between the rollers and lodged between the rollers and guard, causing breaking and bending of parts.

In accordance with the present invention, the elongated guard means, which extends longitudinally of the lower run of the shoe-carrying chain, is pivotally connected to the frame of the tractor in such manner that the lower part thereof can swing outwardly; therefore, when a stone or stones becomes disposed between the side of the chain and the inside wall of the guard means, the guard means can swing outwardly, relieving the strain between the chain and guard means. Eventually, and quite often quickly, the stone is rolled out of the space between guard means and the" chain.

Further objects and advantages will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the invention is illustrated.

In the drawings:

Fig. 1 is a right side view of a tractor showing the improved guard means applied thereto; part of the guard means is broken away to show two of the six rollers usually employed;

Fig. 2 is a top plan view of the fore part of the guard means, part thereof being in section, the section being taken on line 22 of Fig. 1; Fig. 2 is on a larger scale than Fig. 1; and

Fig. 3 is a section view of the guard, the section being taken along line 3-3 of Fig. 1; Fig. 3, like Fig. 2, is on a larger scale than Fig. 1.

While the present invention may be employed on any type of crawler tractor, I have shown the same applied to Model I'D-24 of International Harvester Company, 180 North Michigan Avenue, Chicago 1, Illinois. The tractor 20 comprises a right and left track frame. The right frame only is shown at 21. 'Ihese frames are each provided with a plurality of rollers 23 which extend below the lower edge of the frame. The shafts for the rollers are shown at 25. Rollers 23 ride upon the top surface 26 of the lower run of an endless chain 27. This chain comprises the usual parallelly arranged pairs of links 28, connected with one another and the next adjacent links by pins 29. Each pair of links carries a 2,780,500 Patented Feb. 5, 1957 shoe 30 on the outer surfaces thereof, and these shoes each includes a cleat 31.

Chains 27 each extend about a pair of sprocket wheels including rear sprocket wheel 33 and front sprocket wheel 34. It will be understood that another pair of sprocket wheels and a chain are disposed on the opposite sides of the tractor 20. Idler rollers 36 carry the upper runs of the chains 27.

Either the rear or front sprocket wheels or all may be driven by an engine (not shown) but housed under hood 37. Such dn'ving would be through transmission mechanism (not shown) but included in the casing 39 below the driver seat 40.

The guard means is herein shown as a one piece guard 42; it extends horizontally, i. e., longitudinally of the lower run and is arranged alongside the lower run of the chain 27. It will be understood that four such guard means are provided, a pair being provided for each chain, disposed on opposite sides of the lower run of each chain.

A series of brackets for pivotally supporting the guard 42 is disposed on the outside and inside wall of each frame 21. The outer brackets are shown at 43; these brackets are welded to the frames 21. Holes are provided in these brackets, all of a series being horizontally aligned for receiving pins 45. Each of the pins 45 extends through a pair of lobes 47, extending upwardly from the upper edge of the guard 42. The pins 45 are held in place by cotter pins 46. Thus each of the guards is arranged to swing outwardly, i. e., laterally of the longitudinal length of the lower run of the chain.

Inasmuch as the sides of the frame. 21 extend outwardly beyond the chain, the front end 49 (as well as the rear end) of each of the guards 42 is bent inwardly, as is shown in Fig. 2, so as to decrease the clearance between the ends of the guard and the chain.

Thus it will be seen that those rocks or stones which find their way into the space between the guard 42 and chain, cannot cause jamming or clogging between the guard and chain, since the guard can swing outwardly to release the rocks or stones.

While the form of embodiment herein shown and described constitutes a preferred form, it is to be understood that other forms may be adopted falling within the scope of the claims that follow.

I claim:

1. In a tractor having a frame, front and rear sprocket wheels, an endless chain trained about the Wheels and forming tread shoes for the tractor, and rollers interposed between the top surface of the lower run of the chain and the frame for supporting the frame, in combination, rock guard means extending longitudinally of and disposed alongside of the lower run of the chain; means at the upper portion of the guard means for pivotally supporting the guard means on the frame on an axis lying substantially parallelly ofthe longitudinally extending guard means.

2. In a tractor having a frame, front and rear sprocket wheels, an endless chain trained about the wheels and forming tread shoes for the tractor, and rollers interposed between the top surface of the lower run of the chain and the frame for supporting the frame, in combination, a one-piece rock guard extending longitudinally of and disposed alongside of the lower run of the chain; means at the upper portion of the guard for pivotally supporting the guard on the frame on an axis lying substantially parallelly of the longitudinally extending guard means.

3. In a tractor having a frame, front and rear sprocket wheels, an endless chain trained about the wheels and forming tread shoes for the tractor, and rollers inter- PQSYQd bet een. the ten surface of the lower run f h chain and the frame for supporting the frame, in combination, rock guard means extending longitudinally of and d pose l side of the lower run of the chain; a plurality of brackets secured to the, frame, above the lower u o ai chain and p ced al ng the length or the guard means; pivot pins for pivoting the, guard means to the brackets, said pins being connected with the upper part of the guard means and each having its axis lying substantially parallelly of the longitudinally extending guard means.

4. In a tractor having a frame, front and rear sprocket wheels, an endless chain train-2d about the wheels and forming tread shoes for the tractor, and rollers interposed between the top surface of the lower run of the chain and the frame for supporting the frame, in combiuati n, a onmpiece rock guard extending longitudinally of and disposed alongside of the lower run of the chain; a plurality of brackets secured to the frame above the lower run of said chain and spaced along the length of the guard; pivot pins for pivoting the guard to the brackets, said pins being connected with the upper part of the guard and each having its axis lying substantially parallelly of the longitudinally extending guard.

References Cited in the file of this patent UNITED STATES PATENTS 1,130,018 Fittings Mar. 2, 1915 1,217,729 Ermatinger Feb. 27, 1917 1,647,540 Rasmussen Jan. 31, 1924 1,741,878 Rasmussen Dec. 31, 1929 1,992,702 Koop Feb. 26, 1935 

